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Wednesday, March 28, 2018

How do scientists know we've only discovered 14% of all living species?

How do scientists know we've only discovered 14% of all living species?


How do scientists know we've only discovered 14% of all living species?

Posted: 27 Mar 2018 11:32 PM PDT

Why do we sometimes have problems telling apart left and right, but not up and down?

Posted: 27 Mar 2018 09:00 AM PDT

Edit: Just for clarification: I don't mean the absolut terms of up and down like relative to the earths gravity, those make sense to me as well. I mean the relative up and down, like relative to your field of view.

submitted by /u/ifif1000
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Do other social species (like ants, for example) organize themselves into rural, suburban, and urban areas, similar to humans?

Posted: 27 Mar 2018 09:41 AM PDT

I was recently thinking about how the high efficiency of services and goods access in urban areas seem to make their development inevitable, particularly with advancing technology. And many other potential reasons, but I won't get into the weeds.

But obviously, there are plenty of humans who do still live in rural and suburban areas.

So I'm wondering if other social species have a similar spectrum of living areas, and if so, what contributes to why some animals stay rural whereas others are more suburban or urban. Have there been any studies published on this?

submitted by /u/MRC1986
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Say we scale down an aircraft proportionately (say, all dimensions divided by a factor of 2). What happens to the lift, drag, wing efficiency, etc? What are the scaling laws here?

Posted: 27 Mar 2018 01:38 PM PDT

How does having more trees on a hillside help to prevent landslide?

Posted: 28 Mar 2018 07:32 AM PDT

I've heard some explanation long time ago about the roots "holding on" to the soil, what is the exact mechanism? I don't suppose the roots have any sort of "grip" in the conventional sense.

submitted by /u/finally_got_username
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What methods have been suggested to directly observe right handed neutrinos?

Posted: 28 Mar 2018 03:37 AM PDT

If they don't interact through Standard Model interactions, how can we ever directly observe them? And if we can't, how do we know that they exist?

submitted by /u/fiddybucks420
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Do all orbitals have infinite ranges with only specific regions of high probability of finding an electron? And if so, does it mean that technically an atom is infinite in size?

Posted: 28 Mar 2018 06:11 AM PDT

Do any young animals cry like human children?

Posted: 27 Mar 2018 07:21 PM PDT

Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology

Posted: 28 Mar 2018 08:07 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Economics, Political Science, Linguistics, Anthropology

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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whats the difference between single double and coaxial prop thrust?

Posted: 27 Mar 2018 10:26 PM PDT

At fixed diameter and rpm, what is the difference in potential thrust between
A. a single full diameter rotor blade.
B. An X shaped blade of the same diameter
C. two full diameter rotor blades as in example A sharing a common axis but spinning in counter to one another

Does B=2A? Are B and C different in potential thrust output?

submitted by /u/PoweRaider
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Nuclear Reactor : Control rods - What causes the difference in reactivity of the core when control rods are withdrawn at full power and all control rods are inserted at zero power?

Posted: 27 Mar 2018 05:32 PM PDT

Hi all,

I am interested to understand the effect of control rods during a shutdown margin and how the value of keff could change between the two scenarios.

Many thanks for your help

submitted by /u/helix_413
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Why can we get some diseases only once when others require vaccines every few years ?

Posted: 27 Mar 2018 10:31 AM PDT

Unless I'm completely mistaken some diseases like chickenpox or mumps you can only get once whether it be by actually being affected by it or by getting vaccinated for it and then you never get that disease again.

But then for most vaccines you're supposed to get back every few years to get vaccinated again like for tetanus for example.

I understand that acquired immunity comes from your lymphocyte B memory cells and you need to get vaccinated every few years because their numbers decrease over the years if you don't get exposed to the disease but why do some diseases like chickenpox only require 1 vaccination for your entire life ?

submitted by /u/Elvenstar32
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Do polarized lenses completely block the light when kept at an angle 90 degree?

Posted: 27 Mar 2018 10:14 PM PDT

If yes the must be the darkest thingies

submitted by /u/homosapien__
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What are some "anomalous" or unexplained fossils/biological materials that we've found?

Posted: 27 Mar 2018 04:00 PM PDT

(Sorry for the wonky title, automod doesn't let you submit topics that don't end with a question mark.)

By "unexplained" I just mean "Things we don't have an explanation for just yet." (E.g. The "Devils Corkscrews" before we figured out what they were.)

I was thinking about the topic because of this article which describes a human effort to protect coral reefs. If this effort is successful, and humanity were to forget about it, then wouldn't future archeologists be confused (at least at first) as to how it happened?

Is there anything we have now that we can't explain just yet, or that we can explain but that had an interesting explanation?

submitted by /u/ThiZ
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Are mascara and make-up a problem in satellite clean rooms?

Posted: 27 Mar 2018 08:43 AM PDT

I just happened to see photos of people in a satellite clean room and one had mascara and make-up. I was thinking about potential contamination of the device if some mascara or make-up dust would fall on the device.

submitted by /u/thargos
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How do gravitational fields interact with each other?

Posted: 27 Mar 2018 01:59 PM PDT

When I think of how gravity works from the planetary scale to the galactic and universal scale, I get a bit lost with the mental image I make.

Here's my imagination:

The sun is the obvious gravitational well in the solar system, therefore we are within its "web" so to speak. We constantly fall towards it, such as the moon does the Earth. But that is where I get bundled up, and it applies all the way to the larger scale. Are gravitational fields within other fields amplified or reduced in any way?

I guess some visuals would help me here. I understand the concept but have a hard time putting an accurate picture together.

submitted by /u/PressingSoda
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The Australian Cricket Scandal: How does rubbing tape against the ball make it move unpredictably?

Posted: 27 Mar 2018 11:24 AM PDT

So lately there has been this huge controversy in Cricket where the Australian team was caught ball tampering. The bowler apparently rubbed the ball with yellow tape and "roughed up the ball on one side," making it more challenging for the batsmen to hit.

How does A). Rubbing a ball with tape rough it up? Is tape really that damaging to the surface of a cricket ball What does tape do to the surface of cricket ball.

B). How much of a difference does that actually make? How does the trajectory of the ball change when one side is more rough? How uneven does the surface of the ball have to be to make a noticeable difference?

https://www.nytimes.com/2018/03/26/sports/cricket/australia-cricket-scandal.html

submitted by /u/Yakety_Sax
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What is the Calabi-Yua manifold ?

Posted: 27 Mar 2018 08:01 AM PDT

I'd really like to learn more about it but I can't find much about it. I'd appreciate if someone could take the time to explain it to me, Thanks.

submitted by /u/Ampdoesntmiss
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How do we know that the solar system is a remnant of an earlier one?

Posted: 27 Mar 2018 10:18 PM PDT

[Biology] Does human testicular volume change throughout adulthood?

Posted: 27 Mar 2018 07:53 AM PDT

Are there any landforms that exist in theory, but of which there no current examples on Earth?

Posted: 27 Mar 2018 06:40 AM PDT

Do molten metals in the Earth's mantle, outer, and inner layers separate by density?

Posted: 27 Mar 2018 01:40 PM PDT

Tuesday, March 27, 2018

Are there any resources that Earth has already run out of?

Are there any resources that Earth has already run out of?


Are there any resources that Earth has already run out of?

Posted: 26 Mar 2018 10:26 PM PDT

We're always hearing that certain resources are going to be used up someday (oil, helium, lithium...) But is there anything that the Earth has already run out of?

submitted by /u/faux-tographer
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Why are some charging cables faster than others even when using the same power supply?

Posted: 26 Mar 2018 03:18 PM PDT

Why is it so difficult to manufacture graphene in industrial quantities?

Posted: 26 Mar 2018 11:37 PM PDT

Graphene seems to be such an incredible material with so many cutting edge applications.

Why is it that we can't manufacture it in any decent quantities? Does it just need a gigafactory style investment to obtain economies of scale or is there something that is lacking in our understanding of the physics that is preventing us from an efficient means of production?

submitted by /u/n8ores
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How long did recombination (photon decoupling) actually take?

Posted: 26 Mar 2018 06:43 PM PDT

Ok, so in the beginning, the universe was too hot and energetic for nuclei to hold on to electrons. Therefore photons had a very short mean free path to travel, and the whole universe was opaque. So far, so good.

Then, "378,000 years after the big bang", the universe had cooled down sufficiently for neutral atoms to form and became transparent. The one thing that I find gets glossed over in all the texts I've read is how long this process actually took. Was it fairly instantaneous across the entire universe, did it take weeks, months, thousands of years?

While the process was ongoing if you were in one of the transparent bits of the universe and looked towards a yet opaque bit, what would it look like? White? Black? Red?

submitted by /u/OnDrugsTonight
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Why do knives cut better when you slide the blade across the thing you're cutting?

Posted: 26 Mar 2018 06:27 PM PDT

You can't really push a knife through something. Most often it cuts a heck of a lot better if you SLIDE the knife (almost like sawing, but only in one direction.)

For example, cutting raw chicken. If you try to just press your knife down against it, it doesn't really work, but if pull the knife back as you're cutting, it cuts great.

Another example... You can press your finger against the sharp edge of a blade without hurting yourself, but as SOON as you slide your finger across the blade, you get a cut. Why?

Of course, this is all related to how sharp the knife is, but the question still stands.

submitted by /u/corrado33
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Can you change the wavelength of coloured light?

Posted: 26 Mar 2018 11:25 PM PDT

With magnetism or something. I know phosfloresence does it, but is there another mechanism? Does it work with non-uv light, if so is it still called that? Does it always go towards ir?

submitted by /u/sobertomato
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How do multifocal Intra-ocular lenses work?

Posted: 26 Mar 2018 05:39 PM PDT

A recent study has suggested some of TRAPPIST-1's planets may have 'too much water for life'. How does 'too much water' prevent a terrestrial planet from forming life?

Posted: 26 Mar 2018 11:48 AM PDT

If sulfuric acid has a pH 2.75 (give or take a little) and Coca-Cola has a pH of 2.53 why does drinking sulfuric acid kill you but drinking Coke does not?

Posted: 26 Mar 2018 01:14 PM PDT

What would happen to a hurricane (or tropical storm) that crosses the equator? Would the coriolis effect break it apart? Would it somehow reverse its rotation?

Posted: 26 Mar 2018 01:33 PM PDT

How do surgeons attach blood vessels to artificial hearts?

Posted: 26 Mar 2018 09:21 AM PDT

I'm specifically referring to the artificial heart that was recently in the news. see here.

I've read that blood vessels are normally attached by sewing which obviously won't work here. I've read that glue is not reliable for blood vessels. That leaves me thinking about something like the hose clamps used in engines, but surely that isn't reliable either.

So what prevents the blood vessel from slipping off the device in the short term? Does the blood vessel eventually fuse with the device? If not, what is the durability of the attachment mechanism? Wouldn't the "ends" of the blood vessel fray or deteriorate over time?

submitted by /u/scratch1234
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If I were to fill a cup with ice, and then water (all the way to the rim) to fill in the remaining space, would the water overflow once all the ice melted?

Posted: 26 Mar 2018 05:58 PM PDT

What's an anchor protein?

Posted: 27 Mar 2018 01:41 AM PDT

Someone told me that when cancer cells lose them, the cancer can become metastatic.

submitted by /u/StrangeSwordfish
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How does sound dampening work on trains?

Posted: 26 Mar 2018 11:32 AM PDT

Shouldn't trains produce very loud noise, considering their wheels are metal and are rolling on a metal rail? What measures can be (and are) taken to lessen that noise? Can a new train be used on an old track without noise and vice versa?

submitted by /u/HelloWorld002
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How do we measure gas levels of an exoplanet's atmosphere?

Posted: 26 Mar 2018 02:26 PM PDT

Methinks this would be impossible with current technology since we have to use a host star to even theorize an exoplanet's existence.

submitted by /u/Umbross13
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What exactly is going on in the brain if a patient has "the most aggressive form of brain cancer" that could make them die quickly? How does brain cancer work exactly and how differently does it work when compared to other cancers?

Posted: 26 Mar 2018 10:36 AM PDT

I watch this series on TV called "The Good Doctor" which is airing in the US and Canada, and in this season's final episode (airing this week) according to a preview airing after last weeks episode, one of the most important characters in the show (the head of the hospital where the series revolves around/in, and the father figure/mentor to the main character who has both autism and savant syndrome) gets diagnosed with "the most aggressive form of brain cancer", and everyone except the main character accepts the (possibly terminal) diagnosis. The main character still thinks he may able to save his mentor and father figure somehow (judging on the preview of this weeks episode that aired last week.)

Preview of this week's episode in case you want to take a look yourself, I found on the related subreddit, /r/GoodDoctor. In this preview, it doesn't specify which kind of brain cancer it is other than it is "the most aggressive" form out there.

So what I am wondering, as someone who has followed this show since the beginning (and having seen the main character grow up in this environment and interact with the other characters throughout all the episodes) and wanting more information on this: What exactly (scientifically) is going on in the brain of a patient that has "the most aggressive form of brain cancer" possible that could/would make them die quickly? Also, how does brain cancer work exactly and how differently does it work when compared to other cancers of the human body?

submitted by /u/urbanracer34
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How did the first cells replicate?

Posted: 26 Mar 2018 09:31 AM PDT

DNA polymerase and RNA polymerase enzymes are integral for cell replication as far as i know, but they are quite complex molecules. Were they already present at the beginning of life or were there other methods of replication of DNA?

submitted by /u/FinnishViking
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Have there been studies of chemical bioaccumulation in humans?

Posted: 26 Mar 2018 11:39 AM PDT

I'm aware of bioaccumulation studies in animals, but not in humans. This is almost a forensic medicine question. Is mercury bioaccumulation a fingerprint of people who eat lots of fish, for example? What other chemicals are humans bioaccumulating? Although humans eat more varied food sources, are there still certain food sources that leave distinct chemical fingerprints?

submitted by /u/siliconlife
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What's the difference between a car's object detection system based on computer vision compared to an AI neural network?

Posted: 26 Mar 2018 03:11 PM PDT

Asking because of this article about the Uber accident

Recent developments in artificial intelligence, like deep neural networks, have led many to believe that it is now easy to develop a highly accurate object detection system and that the decade-plus experience of incumbent computer vision experts should be discounted.

submitted by /u/smartse
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Monday, March 26, 2018

Can the ancient magnetic field surrounding Mars be "revived" in any way?

Can the ancient magnetic field surrounding Mars be "revived" in any way?


Can the ancient magnetic field surrounding Mars be "revived" in any way?

Posted: 26 Mar 2018 03:58 AM PDT

How does the ISS handle debris on its solar panels? How often does the ISS get hit with debris?

Posted: 26 Mar 2018 04:58 AM PDT

If elephants (and other animals with long trunks like mammoths) went extinct millions of years ago, would we know they had long trunks from fossils? How would we know that?

Posted: 25 Mar 2018 06:58 PM PDT

What is happening during a Mandelbrot zoom?

Posted: 25 Mar 2018 09:38 PM PDT

I recently found out that watching Mandelbrot zoom's on YouTube is a ton of fun.

https://www.youtube.com/watch?v=aHkQjdh14cc

I don't know a lot about math. I understand the function and I understand the concept, but what the heck is going on with this video?

submitted by /u/lb8ovn
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Why is mercury so dangerous to be touched or ingested?

Posted: 25 Mar 2018 11:29 AM PDT

What happens on a cellular level?

submitted by /u/tjmorki5
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Relative to their size, how far away are galaxies to each other?

Posted: 25 Mar 2018 02:48 PM PDT

For example; is the average distance between galaxies 10,000 times their diameter?

submitted by /u/RevivedBear
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Do scalars always add?

Posted: 26 Mar 2018 08:19 AM PDT

I'm specifically thinking about positive point charges. When calculating the potential at a point between two point charges will they always add? Is that the point of them being scalar?

I'll be the first to admit that physics terminology usually goes over my head.

submitted by /u/2_Legit_2_Knit
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Are solar panels used in space different from the ones used on Earth?

Posted: 25 Mar 2018 12:23 PM PDT

Like taking advantage of more thermal and UV radiation.

submitted by /u/Thorkill
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Why do the bruised portions of apples taste so different from the unbruised portions?

Posted: 26 Mar 2018 07:58 AM PDT

What exactly causes you to instantly lose consciousness with a blow to the head?

Posted: 26 Mar 2018 07:41 AM PDT

I was thinking about this yesterday and thought I'd ask.. I've been knocked out a couple of times over the years due to various cycling fails and don't really understand what happens.

What is it about a sharp blow to the head that causes the instant loss of consciousness? Does it do something physical like scramble signals, or is it a reaction to the impact designed to protect us, or something different entirely? Whatever it is, I'd love to know.

submitted by /u/MoreCamThanRon
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Could desalination plants ever be powered by hydroelectricity?

Posted: 26 Mar 2018 07:26 AM PDT

If a baby is born premature 7 months in the pregnancy after a month is it going to be more or less developed than if it was still in the womb?

Posted: 25 Mar 2018 12:03 PM PDT

Is it going to be bigger, in terms of body weight and rate of growth? Is it going to be stronger? Will its cognitive development start as if it was born after a complete pregnancy or no? Basically after a month will it be able to react to stimuli as a baby that did 9 months in the womb and then a month out or will it behave as a baby born at 8 months?

submitted by /u/Kabniss
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Where do wastewater treatment plants get the "good" bacteria they need to function? How are the good bacteria kept alive, and the bad ones destroyed?

Posted: 25 Mar 2018 11:08 PM PDT

I've heard from a video about wastewater treatment plants that good bacteria is used to eat harmful microorganisms and pathogens from the dirty water as a step in the purification process. Where does the plant initially get the good bacteria from? How does the good bacteria stay alive, but the pathogens die?

submitted by /u/Whiplash32
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Does dark energy have a negative temperature?

Posted: 26 Mar 2018 06:39 AM PDT

What would happen if you stayed in room with only one color of light, such as red? Would your cones adapt or would it be like coming out a cave?

Posted: 25 Mar 2018 02:43 PM PDT

Nuclear Reactors : Control rods - what causes the difference in reactivity worth? Why does regulation limit the number and depth of control rods at full power?

Posted: 26 Mar 2018 05:50 AM PDT

Hi all,

Just a query I have.

I think I have a rough idea that the difference in reactivity worth may be due to the variation in flux distribution ( as a result of the the fuel loading pattern) and that reactivity worth is an important parameter as it specifies the safety margin of a reactor.

If somone could explain in more detail why exactly regulation limits the number and depth at full power that would be great - it would also be interesting to know if there is much variance between international regulation upon this matter and why at full power it is such a problem.

Thanks!

submitted by /u/helix_413
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Why where Fat Man and Little Boy shaped differently?

Posted: 26 Mar 2018 05:20 AM PDT

This never occurred to me until I saw this meme, but why where Fat Man and Little Boy shaped differently? I understand that they where different sizes with different yields, but why where their silhouettes so different from one another?

submitted by /u/LevTheRed
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Does sense of smell degrade with age like with vision and hearing?

Posted: 25 Mar 2018 09:49 PM PDT

Not every galaxy has a black hole at its centre, but what else has a high enough gravitational field to keep stars in orbit?

Posted: 26 Mar 2018 05:14 AM PDT

What's the difference between the Observer Effect and the Uncertainty Principle?

Posted: 25 Mar 2018 01:20 PM PDT

There is an unbelievably large amount of misinformation about both of these things it is hard to get an answer.

From what I understand the uncertainty principle is when you send electromagnetic waves to observe particles but because of how small particles are you need to make the wavelength shorter and the frequency higher so that it interacts with the particle but the more you do this the higher the uncertainty of the position and the velocity of the particle is since the process of doing that disturbs the particle.

I have tried looking up the observer effect and either people start talking about consciousness or I see Neil deGrasse Tyson talking to Joe Rogan and he says that it is the same thing and then I look in the comment section and they say that he is simplifying it or just getting it completely wrong (although the comment section have been known for getting things wrong themselves).

The only other thing is the odd mention of the double split experiment or superposition - both of which I vaguely understand the basic principle behind but I don't really understand what is happening on a Quantum scale.

submitted by /u/Mebzy
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Why can we see our breath when it’s cold out?

Posted: 26 Mar 2018 04:37 AM PDT

Do trees contribute to the environment when they lose their leaves?

Posted: 26 Mar 2018 04:22 AM PDT

For example they photosynthesise to replace oxygen in the atmosphere which is very useful to humans - do they continue to do this during the winter without leaves?

submitted by /u/CasualAppUser
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